Through a three-point bending performance test of nine specimens of U-shaped composite sandwich panels with different Paulownia wood core materials and fiber reinforced polymer(FRP)panel thicknesses,the combined board flexural properties,deformation behavior and failure modes were analyzed.The study found that under the same conditions,section height,width,flange plate and web angle,the thickness of the core material and the FRP panel thickness increased,bending and shearing performances of U-shaped composite sandwich cross-section combination of plate were improved.The test deformation value was compared with the calculated value of Timoshenko beam equation,it was found that the sandwich plate bending deformation values were in agreement with calculated values in the elastic range.